To expiate means to make amends for a wrong you've committed, often through accepting punishment or doing something difficult to show genuine remorse. When you expiate a mistake, you take concrete actions to set things right and demonstrate your regret through meaningful effort.

The word carries a sense of serious wrongdoing requiring serious effort to address. If you accidentally broke your sister's favorite mug, you might apologize and buy her a new one. But if you had deliberately hidden her homework and caused her to fail an assignment, simply apologizing wouldn't be enough. You might expiate that betrayal by confessing to your parents, accepting consequences, and spending weeks rebuilding her trust through consistent honesty.

Historically, many religions developed rituals to help people expiate their sins or moral failures. These weren't meant as shortcuts around guilt, but as formal ways to acknowledge wrongdoing and demonstrate commitment to doing better.

The related noun is expiation: the act of making amends. When someone seeks expiation, they're looking for a meaningful way to address the harm they've caused. Expiation recognizes that some mistakes create real damage that requires real repair, not just words.